The Qingming Festival of the previous year and last year were both on April 5th. Why is it April 4th this year? Isn't everyone saying "Four or Five Qingming"? Why is it different this year? Astronomical popular science experts have stated that although there is a saying among the Chinese people that the Qingming Festival falls on April 5th, the time of Qingming is not fixed and varies between April 4th and 6th in the Gregorian calendar each year. The 24 solar terms are a knowledge system and social practice formed by Chinese people by observing the annual movement of the sun, recognizing the changes in seasonal, climate, phenology, and other aspects of the year. They are a unique creation of ancient Chinese civilization. Yang Jing, a member of the Chinese Astronomical Society and a director of the Tianjin Astronomical Society, introduced that the 24 solar terms divide the ecliptic into 24 equal parts, with the vernal equinox as the zero point. The sun moves every 15 degrees as one solar term, and the equal part is the moment when the solar terms intersect. Each solar term has a dedicated name that reflects information such as climate change, phenological changes, crop growth, precipitation, etc. The 24 solar terms are divided based on the laws of solar motion, and basically, the dates of each solar term do not change much throughout the year. "Spring rain startles the clear valley sky in spring, summer is full of awns, and summer heat is connected. In autumn, there is dew, cold and frost, and winter snow, snow, and winter is slightly cold. In the first half of the year, there will be June 21st, and in the second half of the year, there will be August 23rd. The dates of the two festivals of each month will be fixed, with a maximum difference of one or two days." From this catchy "solar term song", it is not difficult to see that there are two solar terms in the Gregorian calendar every month. In the first half of the year, the festivals will be held before and after the 6th and 21st of each month, and in the second half of the year, they will be held before and after the 8th and 23rd. Yang Jing said that as far as the Qingming solar term is concerned, its date in the Gregorian calendar will only change on April 4, 5 and 6. The Zijinshan Astronomical Observatory of the Chinese Academy of Sciences will be responsible for calculating and publishing the specific day of Qingming. As far as the 21st century is concerned, the Qingming Festival in the vast majority of years occurs on the 4th, followed by the 5th. Due to the fact that the sun does not move at a uniform speed on the ecliptic, the timing of the Qingming Festival varies each year. The Qingming Festival in 2022 falls at 3:20 am on April 5th in the Gregorian calendar, which is early morning; The Qingming Festival in 2023 is celebrated at 9:13 am on April 5th in the Gregorian calendar, which is the morning; The Qingming Festival in 2024 will be held on April 4th at 3:02 pm in the Gregorian calendar, in the afternoon. Among the 24 solar terms, only Qingming has evolved into a traditional festival - Qingming Festival. In order to promote and inherit traditional ethnic culture, in 2008, Qingming Festival was added as a national statutory holiday with one day off, and with weekends off, it was given three days off. Afterwards, on the Qingming Festival, whether it was ancestor worship and tomb sweeping or outings, people had more ample time. (Lai Xin She)